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The increase in zinc (Zn) content in orchard soils caused by successive applications of fertilizers and fungicides to control foliar diseases can modify the structure of the roots of young peach trees. The study aimed to evaluate the effect of the application of Zn doses in soil on the morphological and anatomical structure of the roots and on the growth of young peach plants grafted on three clonal rootstock cultivars. Samples of a Typic Hapludalf were collected, air dried, sieved and subjected to the application of 0, 60 and 120 mg Zn kg−1. After the incubation period, one plant of each rootstock cultivar (Flordaguard, Rigitano and Tsukuba-1) was transplanted into rhizoboxes and grown for 65 days. In the shoots, we determined dry matter production and Zn concentration in tissue. In the roots, we analyzed root morphology using light microscopy. The increase in the availability of Zn in the soil stimulated the production and accumulation of phenolic compounds in the cortex and vascular cylinder of the roots, in addition to increasing the concentration of Zn in plant tissue to values ​​above those considered normal. Rigitano and Tsukuba-1 rootstock cultivars exhibited cell rupture in the cortex, resulting in the formation of intercellular spaces. Flordaguard rootstock cultivar was the least sensitive to morphological and anatomical changes in the root apex and, therefore, may be the most recommended for cultivation in soils with high Zn contents.

Made available in DSpace on 2022-04-28T19:08:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Universidade Federal de Uberlândia In Microlicieae taxonomical delimitation of Lavoisiera, Microlicia and Trembleya is problematic. This study aims to fill this gap by identifying leaf characters that are useful for taxonomy of these genera. Species of Rhynchanthera were also included in this study for comparison, since it is an early-diverging genus of the tribe. Diagnostic characters of Lavoisiera include sessile leaves with spongy parenchyma composed of isodiametric cells, and acute margins with supporting tissue. Trembleya is distinguished by petiolate, microphyllous, and hypostomatic leaves. The presence of depressions on the leaf surface and a homogeneous mesophyll is observed only in species of Microlicia. The leaf characters observed in Rhynchanthera, together with the available phylogenetic studies, were important to indicate evolutionary tendencies in the leaf structure within Microlicieae. Thus, our results indicate a tendency for reduction in leaf size within the tribe, in relation to both the petiole and the lamina. This reduction, which is more pronounced in Microlicia, results in a greater anatomical heterogeneity, due to variations in the organization of both vascular and fundamental tissues. Programa de Pós-graduação em Biologia Vegetal Universidade Federal de Uberlândia Instituto de Biologia Programa de Pós-graduação em Ciências Biológicas (Biologia Vegetal) Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica, Av 24A, 1515 Universidade Federal de Uberlândia Instituto de Biologia Rua Ceará s.n., Bloco 2D Universidade Federal de Santa Maria Departamento de Biologia, Avenida Roraima, 1000, Cidade Universitária Programa de Pós-graduação em Ciências Biológicas (Biologia Vegetal) Universidade Estadual Paulista Instituto de Biociências Departamento de Botânica, Av 24A, 1515

Successive applications of copper-based (Cu) fungicides have increased Cu concentration in vineyard soils, inducing Cu toxicity in young vines and cover crops such as black oat, thus inhibiting growth and development. However, increasing soil phosphorus (P) content can reduce Cu toxicity symptoms. In this context, the aim of this study was to evaluate the effect of Cu toxicity and its alleviation by P fertilization in black oat cultivated in sandy soil. For the experiment, Typic Hapludalf soil samples were air-dried, prepared, and subjected to increasing doses of Cu (0, 30, and 60 mg kg−1) and P (0 and 100 mg kg−1). Subsequently, the soil was incubated and stored in pots, where black oat seedlings were grown for 30 days in a greenhouse. Plant roots subjected to Cu, especially with the highest Cu concentration and without P addition decreased the root cap size, showing early tissue differentiation and lateral root formation near the apical region. Decrease in dry matter (DM) production of roots (50 %) and shoots (67 %) was also observed in the highest Cu concentration. Plants without P addition, regardless of Cu concentration, also had lower root (33 %) and shoot (65 %) DM production. P addition in soil and its increased concentration reduced root anatomical changes and stimulated plant DM production. Therefore, we conclude that excessive Cu concentration alters black oat root anatomical structure, affecting plant growth, especially in sandy soils with low organic matter content. However, P supply can reduce root Cu toxicity symptoms, thus increasing plant dry matter production.